Answer:
A. a person can be prevented from using it.
Explanation:
Excludability -
In economics , a good or service is refereed to as excludable , when it is not allowed to be consumed or used by the consumers who have not paid for the good or services .
And , similarly , non - excludable are the one when a non - paying consumer ca not be prevented from using it .
Hence , the correct statement for Excludability is ( a ) .